v2.3.0.15

Geographic Data (Schedule Of Concentration Of Revenue From Individual Geographic Regions) (Details)	12 Months Ended
	Sep. 30, 2011	Sep. 24, 2010	Sep. 25, 2009
U.S. [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	32.00%	34.00%	35.00%
Japan [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	20.00%	19.00%	21.00%
Europe [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	15.00%	16.00%	17.00%
Taiwan [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	8.00%	9.00%	11.00%
South Korea [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	13.00%	12.00%	8.00%
China [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	6.00%	5.00%	6.00%
Other [Member]
Revenue From External Customer [Line Items]
Concentration of revenue from individual geographic regions	6.00%	5.00%	2.00%

X

- Definition

Concentration Of Revenue From Individual Geographic Regions

+ Details

Name:	dlb_ConcentrationOfRevenueFromIndividualGeographicRegions
Namespace Prefix:	dlb
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

Name:	us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration